Ionomers of low molecular weight copolymer amides

ABSTRACT

The ionomer salt of low molecular weight copolymer reaction product of a copolymer acid of an α-olefin and an unsaturated carboxylic acid, and at least one amino acid compound, and a cation containing material. The unsaturated carboxylic acid is preferably an α, β-ethylenically unsaturated carboxylic acid. The present invention includes a method of preparing the ionomer. The ionomer has excellent compatibility with other polymers, particularly polyamides. The ionomer is useful in a method to flush water from pigments.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention is in the field of low molecular weight olefincopolymers; more particularly, this invention relates to the salts,i.e., ionomers, of low molecular weight copolymers of an α-olefin and anunsaturated carboxylic acid, preferably an α,β-ethylenically unsaturatedcarboxylic acid having up to 100 percent of the carboxylic acid groupsreacted with at least one amino acid. The ionomer is useful for flushingpigments.

2. Description of Related Art

The process of flushing pigments is reviewed in Great Britain Patent No.915,453, and by Apps, Printing Ink Technology, Chemical Publishing Co.,Inc., N.Y., pp.498-500 (1959). Flushing is a process to prepare pigmentdispersions in which the pigments remain finely divided and in asuitable form for further processing such as incorporation intopolymeric compositions and inks.

During the manufacture of pigments an aqueous mass of pigment isproduced. The removal of all of the water can result in the pigmentsagglomerating. Some of the water is removed leaving the finely dividedpigment as a wet cake. The aqueous mass of pigment is mixed with apolyolefin usually of low molecular weight. The mixture is coagulatedand the aqueous phase is removed, typically by heating the composition,optionally in a vacuum. The pigment is dispersed in the low molecularweight polymer which can optionally be pulverized.

Low molecular weight polyethylene waxes are used to flush pigments. Theflushed pigments are useful in polymeric compositions used for fibers,molding compounds, extrusion compounds, sheets, film, and the like.Flushed pigments have been used in compositions based on polyethylene,polyvinylchloride, ABS, polyamides, and polycarbonates, among other.

Low molecular weight olefinic copolymers, particularly low molecularweight ethylene copolymers, are described in U.S. Pat. No. 3,658,741.This patent discloses homogeneous copolymers of ethylene and variouscomonomers including unsaturated acids and their derivatives, such asesters and amides. Examples of the derivatives include methyl acrylate,methyl methacrylate, ethyl acrylate, and dimethylaminoethylmethacrylate.

U.S. Pat. No. 4,381,378 discloses a method for the preparation of lowmolecular weight copolymer salts from low molecular weight copolymeracids of α-olefins and α,β-ethylenically unsaturated carboxylic acids.Preferred copolymers are copolymers of ethylene and acrylic acid.

U.S. Pat. Nos. 4,412,040 and 4,603,172 disclose low molecular weightcopolymer salts for use as lubricants and dispersion aides in plastics.The disclosed salts include salts of low molecular weight copolymers ofα-olefins and α,β-ethylenically unsaturated carboxylic acids. Preferredcopolymers are copolymers of ethylene and acrylic acid.

U.S. Pat. Nos. 3,388,186 and 3,465,059 disclose polyamide compositions.The compositions are made by grafting amino acids or lactams onto abackbone chain containing recurring ethylenic units and reactive sites,such as carboxyl radicals of acid, ester or salt groups, andparticularly acrylic acid esters. The proportion of the copolymerbackbone to the polyamide graft can vary between 2 and 90 percent. Thecopolymers disclosed for use as part of the backbone chain have a numberaverage molecular weight of at least about 13,700 in U.S. Pat. No.3,388,196; and at least 10,000 in U.S. Pat. No. 3,465,059.

U.S. Pat. No. 3,634,543 discloses nucleated graft polymers ofpolycaprolactam on carboxy containing copolymeric backbone. The graftpolymer is prepared by polymerization of caprolactam in the presence ofa copolymer of an olefin and an unsaturated carboxylic acid.

U.S. Pat. No. 4,035,438 discloses an impact resistant mixture ofpolyethylene; a graft polymer of an ethylene/acrylic acid copolymer orethylene/methacrylic acid copolymer as a graft substrate and graftedpolymerized units of ε-caprolactam; and polycaprolactam. The copolymersfor use as graft substrates are those which contain 1 to 10 mol percentof (meth)acrylic acid, preferably from 30 percent to 70 percent in theform of the sodium salt.

SUMMARY OF THE INVENTION

It is desirable to have a low molecular weight copolymer havingstructural groups which enhance compatibility with other polymers,particularly other polymers having a higher molecular weight than thelow molecular copolymer. The present invention is an ionomer of a lowmolecular weight copolymer with carboxyl groups reacted with at leastone amino acid compound or salt thereof. The amide containing ionomerhas improved compatibility with polymers such as polyamides.

The preferred ionomer salt is derived from a low molecular weightcopolymer acid of an α-olefin and an unsaturated carboxylic acid,preferably an α,β-ethylenically unsaturated carboxylic acid. The acidcopolymer has a number average molecular weight of from about 500 toabout 6,000. Preferably, the low molecular weight copolymer acid is acopolymer of ethylene and acrylic acid or methacrylic acid, having anumber average molecular weight of from about 1,000 to about 3,500. Thecopolymer acid has preferably from about 0.8 to about 35, and preferablyfrom 5 to 25 weight percent of the comonomer acid with a correspondingamount of α-olefin.

Up to 100, preferably from about 10 to 100, and more preferably fromabout 50 to 100 percent, of the carboxylic acid groups are reacted withat least one amino acid compound or salt thereof. The amino acid (orsalt thereof) has an amine end group and a carboxylic acid (orcarboxylic acid salt) end group. The amine end group reacts with thecarboxyl end group of the copolymer acid to form an amide group at thereaction site. There is from about 0.1 to about 50, preferably about 0.1to about 40, more preferably about 0.5 to about 30, and most preferablyabout 5 to 25 weight percent based on the weight of the copolymerreaction product of the amide chain derived from the amino acid compoundor salt thereof. The amide chain can be from about 10 to about 30orabout 0.1 to about 10 weight percent of the reaction product dependingon the desired properties.

The average amide chain length reacted at each carboxyl site ispreferably from about 1 to about 250, preferably 1 to 200, with specificembodiments including amide chain lengths of from 1 to 10, and 1 to 5amide groups. There can be longer amide chain lengths of from 100 to 250amide groups. Preferably, there are sufficient amide grafts, ofsufficient length to confer improved compatibility of the copolymerreaction product and another polymer, preferably polyamide. For thepurpose of the present invention amino acid compounds include cyclicamides, i.e., lactams which can be hydrolyzed to form an amino acidcompound. A preferred amino acid compound has the formula H₂ NCH₂(CH₂)_(n) COOH where n is from 0 to 12, and more preferably from 4 to 8.The most preferred amino acid is amino caproic acid or its lactam,caprolactam.

The term ionomer is consistent with the definition in Billmeyer,Textbook of Polymer Science, 2 ed., Wiley-Interscience, a Div. of JohnWiley & Sons, Inc., page 390 (1971), and comprises the salt of theterminal carboxylic acid groups on the amide chain, as well as residualcarboxylic acid groups on the acid copolymer, and a cation from a cationcontaining compound. Preferred cations are from Groups IA, IIA, IIB,IIIA and the transition elements of the Periodic Table of Elements, withsodium, zinc, magnesium, and calcium being most preferred.

Up to 100 percent, preferably 1 to 100, more preferably, 25 to 100, mostpreferably 50 to 100 percent of the total carboxylic acid groups in thereaction product are neutralized with a cation from a cation containingcompound. Preferably, the cation is a metallic cation having a valenceof from 1 to 3. Preferably, the copolymer acid is first reacted with atleast one amino acid compound, and the reaction product is neutralizedto form an ionomer. The carboxyl groups on the amino acid areneutralized by the cation of the cation containing compound to form theionomer. Additionally, carboxylic acid groups which did not react withthe amino acid can also be neutralized. Alternatively, the amino acidcan be neutralized with the cation containing compound prior to beingreacted with the copolymer acid.

The method of the present invention comprises neutralizing up to 100,preferably 25 to 100, and more preferably 50 to 100 percent of the totalcarboxylic acid groups on the reaction product. Preferably, this isconducted above the melting point of the copolymer reaction product, andmore preferably at from 140° C. to 250° C.

The preferred method of preparing the above recited ionomer of thecopolymer reaction product comprises the steps of heating the copolymerof the α-olefin and the unsaturated carboxylic acid, preferably theα,β-ethylenically unsaturated carboxylic acid, to from about 110° C. toabout 300° C., preferably about 150° C. to about 275° C., and morepreferably about 200° C. to about 275° C.; adding a sufficient amount ofat least one amino acid compound to react with up to 100 percent of thecarboxylic acid groups; and conducting reaction of the copolymer and theacid. Preferably, the copolymer acid is preheated to from 110° C. to200° C. and more preferably, 125° C. to 175° C. The reaction ispreferably conducted under an inert atmosphere, such as nitrogen orargon, or under a vacuum.

The present invention also includes a polymer composition and apigmented composition. The polymer composition comprises at least onefirst polymer, preferably a polyamide and the above recited ionomer. Thepigment composition comprises a pigment, at least one second polymercomprising the above-recited ionomer, and optionally, at least one firstpolymer. The first polymer and the ionomer being different. Uniformityof the blend is conferred by compatibility of the ionomer and the firstpolymer. The uniformity leads to improved melt processing, such asextruded strand integrity.

The ionomer salt of the present invention is useful in a method offlushing a pigment of the type wherein water in an aqueous mass ofpigment is flushed with a low molecular weight polymer. The improvementcomprises flushing the aqueous mass of pigment with at least one ionomerof the present invention resulting in a pigmented composition.

The pigmented composition of the present invention can be used in a widevariety of compositions where the pendant amide chains on the reactionproduct enhance compatibility. A particularly useful composition is acomposition comprising the pigmented composition and a polyamidepolymer. Such compositions have excellent uniformity of pigmentdistribution. More importantly, the pigmented composition results in apolyamide composition with uniform pigment distribution evidenced byuniform and enhanced color. The color is actually enhanced by morecomplete pigment dispersion.

DETAILED DESCRIPTION OF THE INVENTION

The present invention includes an ionomer salt of a copolymer reactionof a low molecular weight copolymer of an unsaturated acid and anα-olefin, and an amino acid compound resulting in a copolymer havingpendant amide chains, including polyamides, and a method to make theionomer. The present invention also includes a polymer composition, anda pigmented composition which comprise the ionomer, as well ascompositions which comprise the pigmented composition. The presentinvention further includes a method of flushing pigments with theionomer.

Copolymer acids useful to make the ionomer of the present inventioninclude the copolymer of an α-olefin and an unsaturated carboxylic acid,preferably an α,β-ethylenically unsaturated carboxylic acid orderivative thereof. These copolymers are of low molecular weight, havinga number average molecular weight of from about 500 to about 6,000, andpreferably about 1,000 to about 3,500. Useful and preferred copolymersinclude homogeneous copolymers of ethylene disclosed in U. S. Pat. No.3,658,741, the disclosure of which is hereby incorporated by reference.

The α-olefin preferably has from 2 to 8 carbon atoms and is mostpreferably ethylene or propylene. There is at least about 50, preferablyfrom about 50 to about 99.5, more preferably, about 65 to about 99.2,and most preferably from about 80 to about 98 mol percent of theα-olefin, which is most preferably ethylene.

The unsaturated carboxylic acid or derivatives thereof includes suchcompounds disclosed in U.S. Pat. No. 3,658,741. Useful carboxylic acidsinclude both monocarboxylic and polycarboxylic acids and derivativesthereof, including esters and anhydrides, which are capable of reactingwith the amino acids recited below. Useful carboxylic acids orderivatives thereof include unsaturated monocarboxylic acid containingfrom 3 to 6 carbon atoms and dicarboxylic acids containing from 4 to 8carbon atoms. Specific examples of unsaturated acids copolymerizablewith ethylene include acrylic acid, methacrylic acid, ethacrylic acid,itaconic acid, crotonic acid, maleic acid and fumaric acid. Also usefulare acid halides, amides and esters including acrylyl chloride andacrylamide. Esters which can be used include methyl acrylate, methylmethacrylate, ethyl acrylate and dimethylaminoethyl methacrylate. Alsouseful are monoesters of dicarboxylic acids, such as methyl hydrogenmaleate, methyl hydrogen fumarate, ethyl hydrogen fumarate, and maleicanhydride. Particularly preferred compounds include α,β-ethylenicallyunsaturated acids and derivatives thereof.

A preferred copolymer acid is a copolymer of ethylene and anα,β-ethylenically unsaturated monocarboxylic acid having 3 to 6 carbonatoms. A most preferred α,β-ethylenically unsaturated mono-carboxylicacid is acrylic acid. Most preferred is ethylene acrylic acid copolymerwhich has an acid number in the range from about 1 to about 180, with anacid number from about 40 to 160 being preferred, and an acid numberfrom about 40 to 120 being most preferred. The acid number is determinedby the number of milligrams of potassium hydroxide needed to neutralizeone gram of acid. The number average molecular weight is from about 500to about 5000, and preferably from about 1000 to about 3500. Table Ibelow characterizes preferred ethylene acrylic acid copolymers.

                                      TABLE I                                     __________________________________________________________________________          Softening Pt.                                                                        Hardness                                                                             Density                                                                            Brookfield                                                                           Acid No.                                      Copolymer                                                                           (ASTM E-28)                                                                          dmm    g/cc Viscosity                                                                            mg   Wt %                                     Acid  °C.                                                                        °F.                                                                       (ASTM D-5)                                                                           D-1501                                                                             @140° C. cps                                                                  KOH/g                                                                              Acrylic                                  __________________________________________________________________________    A     108 226                                                                              2.0    0.93 500    40   5                                        B     101 215                                                                              4.0    0.93 650    75   9.4                                      C      92 198                                                                              11.5   0.93 650    120  15                                       __________________________________________________________________________

The copolymer acids are available from Allied-Signal Inc. as A-C®540(A);A-C®580(B) and A-C®143(C).

The low molecular weight copolymer acids can be prepared by any suitablemethod such as described in above referenced U.S. Pat. No. 3,658,741. Ofparticular interest in U.S. Pat. No. 3,658,741 is the passage beginningat column 7, line 36 through column 8, line 6. In accordance with thisprocess, the ethylene desirably constitutes at least 65% by weight ofthe monomer feed and the comonomer from 1.0% to 35% of the feed,preferably 2 to 20% by weight of the feed. Under specific conditions ofvapor phase polymerization the ratios by weight of the monomers in thefeed and in the product are substantially constant. The ratio ofcomonomer between feed and product are at most only minor such thatproducts obtained by the invention contain a major portion of ethyleneand generally 0.8% to 35% by weight of the comonomer, preferably 2.0% to20% by weight of the comonomer. The ratio of comonomer in the product tocomonomer in the feed is preferably within the range of 0.7:1 to 1.8:1.

The acid copolymers useful in the present invention are of low molecularweight ranging generally between about 500 to about 6000 number averagemolecular weight, preferably between about 1000 to about 3500 numberaverage molecular weight, as measured by a vapor pressure osmometer. Thecopolymers also desirably have a Brookfield viscosity not exceedingabout 2000 centipoises at 140° C., preferably between about 200 to about1200 centipoises at 140° C. Of special interest are the copolymers ofethylene and acrylic or methacrylic acid containing from about 1% toabout 20% by weight acrylic acid or methacrylic acid in the copolymer,preferably about 3.5% to about 12%, and further characterized by anumber average molecular weight between about 1500 to about 3500, acidnumber between about 10 to about 200, preferably about 20 to about 130,and hardness (0.1 mm penetration) between 0.5 to 30, preferably 1 to 10when tested at room temperature about 25° C. (77° F.) according to ASTMD-5 using a needle with a load of 100 grams for 5 seconds.

In accordance with the present invention up to 100, preferably fromabout 50 to about 100 and more preferably about 10 to about 30 percentof the carboxylic acid groups are reacted with from about 0.1 to about50, preferably, 0.1 to 40, more preferably about 0.5 to about 30, andmost preferably about 5 to about 25 weight percent based on the weightof the reaction product of at least one amide chain derived from atleast one amino acid compound. There can be from about 10 to about 30,or about 0.1 to about 10 weight percent of at least one amide derivedfrom at least one amino acid. For the purpose of the present inventionamino acid compounds include: amino acids, and cyclic amides, i.e.,lactams which can be hydrolyzed to form amino acids; and derivativesthereof.

Preferably, the amino acid compound is an amino acid monomer which hasthe formula H₂ NCH₂ (CH₂)_(n) COOH where n is from 0 to 12, and morepreferably from 4 to 8; or an amino acid oligomer or polymer derivedfrom this monomer. The most preferred amino acid monomer is aminocaproic acid or its lactam, caprolactam.

Also useful amino acid compounds are derivatives of the amino acidsincluding esters, or lactams of the amino acids. Specific examples ofuseful amino acids include ε-amino-caproic acid; 11-aminoundecanoicacid; 12-aminododecanoic acid; esters, amides and lactams ofmonoamino-monocarboxylic acids, such as ε-caprolactam; ethylε-aminocaproate; lauryl lactam; ethyl-11-aminoundecanoate;11-aminoundecanoamide, and the like. The amino acid can be a polyamide,such as, polycaprolactam. Alternatively, the polyamide can be apolyamide of the type made from a diamine and a dicarboxylic, such aspoly(hexamethylene adipamide), i.e., nylon 66.

The reaction between the amino acid compound and the acid copolymerresults in grafts having the formula ##STR1## wherein x is from at least1, and preferably 1 to 250, and R can comprise at least 2 methylenegroups and preferably from 4 to 8 methylene groups; or be the radical ofa diacid/diamine polyamide.

The average amide chain length reacted at each carboxyl site ispreferably from about 1 to about 250, preferably 1 to 200, with specificembodiments including amide chain lengths of from 1 to 10, and 1 to 5amide groups. There can be longer amide chain lengths of from 100 to 250amide groups. Preferably, there are sufficient amide grafts, ofsufficient length to confer compatibility of the copolymer reactionproduct and another polymer, preferably polyamide. For the purpose ofthe present invention amino acid compounds include cyclic amides, i.e.,lactams which can be hydrolyzed to form an amino acid compound. Apreferred amino acid compound has the formula H₂ NCH₂ (CH₂)_(n) COOHwhere n is from 0 to 12, and more preferably from 4 to 8. The mostpreferred amino acid is amino caproic acid or its lactam, caprolactam.

The copolymer reaction product useful in the present invention ischaracterized by an acid number of from about 10 to about 200,preferably about 25 to about 150, and most preferably about 25 to about75 where the acid number is the number of milligrams of KOH used toneutralize one gram of sample. The copolymer reaction product has aBrookfield viscosity at 140° C. of from about 500 to about 5,000,preferably about 500 to about 2,000, and more preferably about 500 toabout 1,500. The Mettler drop point according to ASTM D-3104 can be atleast about 90° C., and can be from about 90° C. to about 150° C.

The present invention includes methods to make the ionomer. Thepreferred method is to neutralize the reaction product of a copolymeracid and an amino acid. Alternatively, the amino acid can first beneutralized with a cation containing compound and the copolymer acid canbe neutralized with the salt of the amino acid.

In the preferred method of the present invention, the preparation of theabove recited copolymer reaction product comprises the steps of heatinga copolymer of α-olefin and an α,β-ethylenically unsaturated carboxylicacid to from about 110° C. to about 300° C., preferably about 150° C. toabout 275° C., and more preferably about 200° C. to about 275° C.;adding a sufficient amount of at least one amino acid compound to reactwith up to 100 and preferably 50 to 100 percent of the carboxylic acidgroups; and conducting the reaction of the copolymer and the amino acidcompound. Preferably, the copolymer acid is preheated to from about 110°C. to about 200° C. and more preferably, about 125° C. to about 175° C.prior to reaction with the amino acid compound.

The reaction is preferably conducted under an inert atmosphere, such asnitrogen or argon, or under a vacuum. The reaction pressure is notcritical and is preferably conducted at about 1 atmosphere. The reactioncan be conducted continuously or in batches.

The copolymer reaction product is then neutralized by a suitable cationcontaining compound. The cation containing compound can be addeddirectly to the copolymer reaction product. The cation containingmaterial is preferably added in the form of an aqueous slurry and/orsolution to enhance dispersion in the copolymer reaction product. Theneutralization reaction is preferably conducted at a temperature abovethe melt temperature of the copolymer reaction product. Preferably, theneutralization reaction is conducted at from 140° C. to 250° C., andmore preferably form 175° C. to 225° C. The reaction is preferablyconducted at about 1 atmosphere. The reaction can be conductedcontinuously or in batches. The reaction is conducted until a desireddegree of neutralization is attained. Preferred neutralization times arefrom 0.5 to 10, and more preferably from 1 to 5 hours, with 2 to 4 hoursbeing most preferred. Preferably, the reactor has a means, such as acondenser, to remove water introduced into the reactor with thereactants, as well as water formed during the reaction.

Reaction additives to help facilitate the reaction can be added. Aparticularly preferred additive is acetic acid, preferably glacialacetic acid is added to help speed the reaction and make a more uniformionomer. The acetic acid converts metal oxides, and/or hydroxides tomore soluble acetates. This helps to speed the reaction and reduceagglomerates of the metal compound. Preferably, there is at least 0.1,and more preferably from 0.1 to 1.0, and most preferably 0.2 to 0.5percent of the reaction additive based on the weight of the copolymerreaction product. In a most preferred embodiment an aqueous slurry ofthe cation containing compound is combined with the reaction additive,i.e., acetic acid, and this slurry added to a reactor containing moltenpolymer.

Alternatively, the amino acid compound can be first neutralized with thecation containing compound. The formed amino acid metal salt can then bereacted with the copolymer acid in under the same conditions recitedabove for the reaction product of the copolymer acid and the amino acid.

Cations having valences of 1 to 3 can be used to neutralize thecopolymer acid. Preferably, metallic cations are derived from a group ofmetals which can be chosen from Groups IA, IIA, IIB, IIIA and thetransition elements of the Periodic Table of Elements to be used in thisprocess. Metal cations which are preferred are sodium, potassium,magnesium, calcium, barium, zinc and aluminum cations, with sodium,zinc, calcium and magnesium cations being most preferred. Cationcontaining materials can be metal salts including: oxides, hydroxides,acetates, methoxides, oxylates, nitrates, carbonates and bicarbonates.Metallic salt containing materials which are illustrated in the examplesdiscussed below include calcium hydroxide, calcium acetate, magnesiumoxide and zinc acetate.

The copolymer acid can be neutralized up to 100 percent; it is preferredto neutralize the copolymer reaction product to from 15 to 100 percent,and more preferably from 25 to 100 percent neutralization of the totalcarboxylic acid groups using the process of the present invention.Carboxyl groups in the amide chain ends, as well as residual carboxylgroups on the copolymer acid, can be neutralized.

The most preferred ionomer is the ionomer of the reaction product ofcopolymer acid B of Table I neutralized to between about 15 and about100 percent with sodium, zinc, magnesium or calcium cations.

The properties of the ionomer of the present invention will depend uponthe starting materials, and reaction conditions as recited above.However, the ionomers of the present invention have the followingtypical properties. The acid number of the ionomer is lower than that ofthe copolymer acid. Depending on the length of the amide chain, the acidnumber of the ionomer can be from 5 to 25 percent lower than thecopolymer acid. Typical ranges of acid number are from about 8 to about200, preferably about 25 to 150, and more preferably from about 25 to75, where the acid number is defined as above. The ionomer has aBrookfield Viscosity at 190° C. of from 5,000 to 5,000,000, preferably25,000 to 3,000,000, and more preferably 50,000 to 2,000,000. Theionomer has a Mettler Drop Point (ASTM D-3104) of from 90° C. to 200°C., and preferably from 100° C. to 150° C. For certain applications,such as dispersing pigments in polyamides, it is desirable to maintainthe moisture content as low as possible, preferably below 0.5, and morepreferably below 0.1 percent based on the weight of the ionomer.

The present invention also includes a polymer composition comprising atleast one first polymer, and at least one second polymer comprising theabove-recited ionomer. The polymer composition comprises up to 99percent and preferably from 1 to 99 percent of at least one firstpolymer and a corresponding amount of the reaction product. The reactionproduct can lubricate the first polymer consistent with polymerlubrication recited in U.S. Pat. No. 4,412,040. The first polymer isdifferent from the second polymer.

The first polymers include but are not limited to polyamides, such asnylon 6, nylon 66, nylon 4, nylon 11, nylon 12 and like; polyolefins,such as polyethylene and polypropylene; styrene based polymers, such aspolystyrene; polyesters, such as polyethylene terephthalate andpolybutylene terephthalate; ABS (copolymers of acrylonitrile, butadieneand styrene); polycarbonates; phenolic resins.

The present invention includes a pigment composition comprising fromabout 1 to about 50, preferably from about 5 to about 40, and morepreferably from about 15 to about 35 weight percent of above-recitedcopolymer reaction product; from about 1 to about 50, and morepreferably from about 5 to about 40 weight percent of a pigment; andfrom 0 to 98 weight percent of the first polymer. The pigmentcomposition is useful in polymer compositions for molded and extrudedgoods, films and fibers, inks and the like. The ionomer by virtue ofimproved compatibility with the first polymer improves pigmentdispersion consistent with improved dispersion properties recited inU.S. Pat. No. 4,603,172.

Typical pigments include: titanium dioxide, zinc oxide; calciumcarbonate; barite, silica and china clay; lead white; carbon black; redlead; chromate pigments; Venetian Red; Prussian blue; chromic oxide;chrome green; cobalt blue, Phthalo blue, Phthalo green, and azopigments.

There can be from about 0.1 to about 100 parts per hundred parts ofpolymer of the pigment to be dispersed. Preferably there is about 0.1 toabout 50 parts of the material . Lower concentrations of from about 0.1to about 1 part per hundred parts of polymer are useful for directblending of low concentration materials such as colorants. Higherconcentrations of from greater than about 10 parts of material can bedirectly introduced into the polymer. High concentrations of from about10 to about 50 parts of material per hundred parts of polymer are usefulto make master-batches, such as color concentrates, for introductioninto larger quantities of the same or different polymers.

The composition can comprise conventional additives such as colorantsincluding fillers, flame retardants, antioxidants, stabilizers,processing aids, and the like.

Typically, fillers may be selected form a wide variety of minerals,metals, metal oxides, siliceous materials, metal salts, and materialsthereof. Examples of fillers include glass fibers, alumina, feldspar,asbestos, talc, calcium carbonates, clay, carbon black, quartz,novaculite and other forms of silica, kaolinite, bentonite, garnet,mica, saponite, wollastonite, etc. The foregoing recited fillers areillustrative only and are not meant to limit the scope of the fillersthat can be utilized in this invention.

The ionomer of the present invention is useful in a method of flushing apigment, of the type wherein water in an aqueous mass of pigment isflushed away with a low molecular weight polymer. The improvement ofthis invention comprises flushing the aqueous mass of pigment with atleast one ionomer of the present invention.

In the flushing process an aqueous pigment mass comprising finelydivided pigment is in the form of a filter press cake having from about25 to about 60, and more typically from about 30 to about 45 weightpercent of pigment with a corresponding amount of water. The ionomer isadded in a mixing means such as a Sigma blade mixer in amounts asrecited above. Preferably, there is from about 25 to about 75, and morepreferably from about 40 to about 60 percent by weight of pigment and acorresponding amount of the ionomer of the present invention. The amountof water is not included in the weight percent. The mixture is heateduntil the water separates from the pigment and the low molecular weightreaction product, typically at about 90° C. to about 110° C.,preferably, about 90° C. to about 100° C., and most preferably, about90° C. to about 95° C. The process typically takes from 10 to 120minutes and more usually 15 to 30 minutes. At this point a drop in powerto the mixer will be observed. The mixing is continued for a few moreminutes, typically 2 to 5 additional minutes. The water in the mixer isdecanted. A vacuum can be applied to remove the balance of the water.This leaves behind a uniform blend of the pigment and the low molecularweight copolymer reaction product. The process of flushing can beconducted batchwise or continuously with filter press cake and ionomercontinuously or intermittently added as the water is decanted. Theprocess has resulted in a high quality dispersion of the pigment in thecopolymer reaction product.

The flushed pigments result in pigment concentrates which can be furtherdiluted with a first polymer of the type recited above to make pigmentmaster batches. Such dilution can be accomplished by melt blending in asuitable melt blender, such as an extruder. The pigment master batchtypically has from 40 to 80 weight percent of a first polymer andcorrespondingly from 20 to 60 weight percent of the pigment concentrate.

The flushed pigments in the form of pigment concentrates and in pigmentmaster batches are useful in polymeric compositions used for fibers,molding compounds, extrusion compounds, sheets, film, and the like.

The examples set forth below illustrate the nature of the invention andthe manner of carrying it out. However, the invention should not beconsidered as being limited to the details thereof.

EXAMPLE 1

This example illustrates the preparation copolymer reaction productuseful to make the ionomer of the present invention based on an ethyleneacrylic acid copolymer B of Table 1, sold by Allied-Signal Inc. asA-C®580. This copolymer acid is reported to have an acid number of 71.9.4361 grams of A-C®580 were melted in a twelve liter flask. A nitrogenatmosphere was maintained at all times. The copolymer was heated to 116°C., at which time 713 gms of 6-aminocaproic acid powder was added. Themixture was continually stirred. The temperature was increased and at149° C. the evolution of water was observed. The water was allowed todistill. At 156° C. water was evolving vigorously. The temperature wasthen maintained at 160°-162° C. for three hours. After three hours at160° C., the flask was discharged, at which point the material had anacid number of 65.1. Acid number is based on the milligrams of KOHneeded to neutralize a gram of sample.

EXAMPLE 2

Pilot plant runs were made to make the copolymer reaction product usefulto make the ionomer of the present invention. The copolymer acid usedwas A-C®580 described above. The amino acid used was a polycaprolactamhaving a number average molecular weight of about 18,000, and a formicacid viscosity of about 50. Where indicated the polycaprolactamcontained minor amounts of heat stabilizers. The polycaprolactam was astraight chain polymer terminated at one end with an amine group and atthe opposite end with a carboxylic acid group.

A charge of 550 pounds (250 kg) copolymer acid was first premelted in a200 gallon (0.76m³) tank at 145° to 150° C. under a nitrogen sweep atabout 1 atm.

The molten copolymer acid was fed to a 200 gallon (0.76m³), stirredreactor which had a condenser to remove moisture flashing off during theformation of the reaction product. The copolymer acid was heated toabout 158° to 162° C. and 155 pounds (70 kg) of the polycaprolactam wasgradually added. The reactor was closed and heating continued to 260° C.for eight hours with agitation.

Seven batches were made using the stabilized polycaprolactam (Runs 1-7)and two batches were made using the same polycaprolactam withoutstabilizers (Runs 8,9). Results are reported in Table 2 below.

                                      TABLE 2                                     __________________________________________________________________________        PARTS            METTLER BROOKFIELD                                           PER 100                                                                            Rx TEMP                                                                             ACID NO.                                                                            DROP POINT                                                                            VISC. @                                          RUN AC580                                                                              (°C.)                                                                        (°C.)                                                                        (°C.)                                                                          140° C. (Cps)                             __________________________________________________________________________    1   28.2 250   54.4  96.2    1575                                             2   28.2 270   54.5  97.0    1730                                             3   28.2 260   54.3  96.8    1520                                             4   22.6 250   57.1  96.6    1488                                             5   17.0 250   60.5  96.1    1375                                             6   28.2 250   54.9  95.3    1562                                             7   28.2 260   54.5  95.6    1542                                             8   28.2 260   54.9  96.1    1777                                             9   28.2 260   55.3  96.2    1825                                             __________________________________________________________________________

EXAMPLE 3

The procedure of Example 2 was repeated resulting in a reaction producthaving an acid number of 51.1; a Brookfield viscosity at 140° C. of 1168centipoise; and a Mettler Drop Point of 100.7° C.

The copolymer reaction product had a uniform and white appearance. Thefeel was that of a hard waxy material. As indicated by the relativelylow Mettler Drop Point values, this material is readily melt blendablewith other polymers.

EXAMPLE 4

The pilot scale Runs in Example 2 were neutralized with zinc oxide toform zinc ionomer.

The copolymer reaction product in each of the Runs of Example 2 werecooled to 220° C. An aqueous slurry of zinc oxide was prepared from zincoxide powder, Kadox 920, supplied as a fine powder by the N.J. Zinc Co.The slurry contained 27 pounds (12.2 kg) of zinc oxide, 243 pounds(110.2 kg) of water, and 1.1 pounds (0.5 kg) of glacial acetic acid. Theslurry was charged to the reactor at a constant rate, with agitation,over a period of 3 hours. Water coming off from the reactor was removed.The reactor was continually monitored to assure that no excessivefrothing occurred. Upon completion of the addition of the zinc oxideslurry, agitation was continued and the temperature maintained at from220° C. to 224° C. for three hours. This stirring period was used todissolve the zinc oxide and to remove moisture. The desired moisturecontent is a maximum of 0.1%. Upon completion of the reaction theionomer was removed. The results of Runs 1 to 9 from Example 2 convertedto ionomer are summarized in Table 3 below.

                  TABLE 3                                                         ______________________________________                                                                    ASTM-                                                   Rx       BROOKFIELD   D-5    EXTRUSION                                        TEMP.    VISC. @      DECI   EVALU-                                     RUN   (°C.)                                                                           190° C. (cps)                                                                       MM     ATION                                      ______________________________________                                        1     200       47,000      0.6    Fair                                       2     220      240,000      .8     Very Good                                  3     220      220,000      1.2    Very Good+                                 4     220       45,500      .8     Fair                                       5     220       38,200      1.2    Good                                       6     220      180,000      .7     Good                                       7     220      220,000      1.2    Very Good                                  8     220      102,000      .9                                                9     220      100,00       1.0                                               ______________________________________                                    

EXAMPLE 5

The compatibility of the ionomer of the present invention with fibergrade nylon was indicated by its ability to be melt blended andsatisfactorily extruded as a polymer composition. A mixture of 30% byweight of the ionomer Runs 1-7 of Example 2 was made with 70% by weightof fiber grade nylon 6, supplied by the Firestone Tire and Rubber Corp.as Firestone C-200, in in pellet form. The mixture was extruded througha 11/4 inch, single screw Brabender extruder, having a barrel length todiameter ratio of 24 to 1, at 250° C. with a 7.5 pounds per hour feedrate. The sample extrusion performance was based on the overallextrudability of a 1/8 extruded strand. The integrity, appearance, andobserved melt strength were considered. Overall results are summarizedin Table 3 above.

EXAMPLE 6

This example illustrated a typical pigmented composition. The pigmentused was phthalocyanine (Phthalo Blue) from Sun Chemical Company,supplied as press cakes which were 30-40 weight percent pigment and acorresponding amount of water.

The amount of pigment in the press cake was determined and a mixture wasmade based on equal weights of the ionomer of the present invention andpigment, excluding the weight of the water.

The ionomer used was of the type made in Examples 1-3. The ionomer washeated in a Sigma Blade Mixer until it melted (about 100° C.). Half ofthe press cake was fed into the mixer and after 15 to 20 minutes, thewater from the press cake breaks (comes out of press cake) and waspoured off. The balance of the press cake was added and after another 15to 20 minutes, the balance of the water breaks and was poured off. Thewater initially appeared blue and as the pigment was wetted by theionomer, the water cleared and was decanted. The mixture cooled and thepigmented composition was a brittle plastic hard wax. The compositionwas broken into pellet size pieces suitable for extrusion. The pigmentedcomposition was a uniform deep blue color having 50 weight percentionomer and 50 weight percent pigment.

EXAMPLE 7

Pigment concentrates of the type made in Example 6 were extruded withfiber grade nylon at 50 percent by weight resulting in a pigment masterbatch composition having 25% by weight pigment. The master batch wasextruded with fiber grade nylon at levels of 0.5 and 0.25 weight percentpigment and spun into the resulting carpet fiber. The fiber wassatisfactory and had uniform and excellent color quality.

While exemplary embodiments of the invention have been described, thetrue scope of the invention is to be determined from the followingclaims.

What is claimed is:
 1. An ionomer of a copolymer reaction product of acopolymer acid of an α-olefin and an unsaturated carboxylic acid saidcopolymer acid having a number average molecular weight of from 500 toabout 6,000 with at least one amino acid compound having an averagechain length from about 1 to about 250 amino acid monomer units, whereinthe amino acid compound comprises from about 0.1 to about 50 weightpercent based on the total weight of the copolymer reaction product saidcopolymer reaction product being neutralized in excess of zero percentand up to 100 percent neutralized with at least one cation from thegroup consisting of metallic cations having a valence of 1 to
 3. 2. Theionomer as recited in claim 1 wherein the amino acid compound is derivedfrom an amino acid monomer of the formula H₂ NCH₂ (CH₂)_(n) COOH where nis from 0 to
 12. 3. The ionomer as recited in claim 2 where n is from 4to
 8. 4. The ionomer as recited in claim 3 where the amino acid monomeris aminocaproic acid.
 5. The ionomer as recited in claim 1 where theα-olefin is selected from ethylene and propylene.
 6. The ionomer asrecited in claim 5 where the α-olefin is ethylene.
 7. The ionomer asrecited in claim 1 where the carboxylic acid is an α,β-ethylenicallyunsaturated carboxylic acid.
 8. The ionomer as recited in claim 7 wherethe α,β-ethylenically unsaturated carboxylic acid is selected fromacrylic acid, methacrylic acid, crotonic acid, maleic acid and fumaricacid, and mixtures thereof.
 9. The ionomer as recited in claim 7 wherethe α,β-ethylenically unsaturated carboxylic acid is acrylic acid. 10.The ionomer as recited in claim 1 wherein the amino acid compoundcomprises from about 10 to about 30 weight percent of the copolymerreaction product.
 11. The ionomer as recited in claim 1 wherein theamino acid compound comprises from about 0.1 to about 10 weight percentof the copolymer reaction product.
 12. The ionomer as recited in claim 1wherein the copolymer comprises about 65 to about 98 mol percent of theα-olefin and about 2 to about 35 mol percent of the α,β-ethylenicallyunsaturated carboxylic acid.
 13. The ionomer as recited in claim 12wherein from about 50 to about 100 mol carboxylic acid groups arereacted with the amino acid compound.
 14. The ionomer as recited inclaim 1 where the amino acid compound is a polyamide.
 15. The ionomer asrecited in claim 1 wherein the cation is of a metal selected from thegroup consisting of Groups IA, IIA, LB, IIIA and the transition elementsof the Periodic Table of Elements.
 16. The ionomer as recited in claim15 wherein the cation is selected from the group consisting of sodiumpotassium, magnesium, calcium, barium, zinc and aluminum.
 17. Theionomer as recited in claim 15 wherein the cations are supplied in theform of cation containing compounds selected from the group consistingof metal: oxides, hydroxides, oxylates, acetates, bicarbonates,methoxides and nitrates.
 18. The ionomer as recited in claim 17 whereinthe cation containing compounds are selected from the group consistingof sodium hydroxide, magnesium oxide, calcium hydroxide, calciumacetate, zinc oxide, zinc acetate and aluminum hydroxide.
 19. Theionomer as recited in claim 1 wherein 25 to 100 percent of thecarboxylic acid groups are neutralized.
 20. A method comprisingneutralizing in excess of zero percent and up to 100 percent of thecarboxylic acid groups of a copolymer reaction product of a copolymeracid of an α-olefin and an unsaturated carboxylic acid said copolymeracid having a number average molecular weight of from about 500 to about6,000 reacted with at least one amino acid compound, the resultantcopolymer reaction product being neutralized with at least one cationfrom the group consisting of metallic cations having a valence of 1 to3.
 21. The method as recited in claim 20 wherein from 25 to 100 percentof the carboxylic acid groups are neutralized.
 22. The method as recitedin claim 20 wherein the neutralization reaction is conducted above themelting point of the reaction product.
 23. The method as recited inclaim 20 wherein the cation containing compound is added as an aqueouscomposition.
 24. A method to make a copolymer reaction productcomprising the steps of:heating a copolymer acid of an α-olefin and anα,β-ethylenically unsaturated carboxylic acid, the copolymer acid havinga number average molecular weight of from about 500 to about 6,000 fromabout 110° C. to about 300° C.; adding a sufficient amount of at leastone amino acid compound to react with up to 100 percent of thecarboxylic acid groups; conducting the reaction of the copolymer acidand the amino acid compound to form the copolymer reaction product; andneutralizing in excess of zero percent and up to 100 percent of thecarboxylic acid groups of the reaction product with at least one cationfrom the group consisting of metallic cations having a valence of 1-3.25. The method as recited in claim 24 wherein 25 to 100 percent of thecarboxylic acid groups are neutralized.
 26. The method as recited inclaim 24 wherein the reaction of the copolymer acid and amino acid isconducted at from 150° C. to 275° C., and the neutralization isconducted at 150° C. to 250° C.
 27. The method as recited in claim 24wherein the α-olefin is ethylene, the α,β-ethylenically unsaturatedcarboxylic acid is selected from the group consisting of acrylic acidand methacrylic acid, and the amino acid compound is derived from amonomer which has the formula H₂ NCH₂ (CH₂)_(n) COOH where n is from 0to 12.